#ifndef TRIANGLE_H
#define TRIANGLE_H
#include <iostream>
int detect(double a ,double b,double c )
{
    if(!(a>0&&b>0&&c>0))
    {
        std::cerr<<"input must be positive numbers!"<<std::endl;
        return -1;
    }
    if(!((a+b)>c&&(b+c)>a&&(a+b)>c))
    {
        std::cerr<<"can not generate a triangle!"<<std::endl;
        return -1;
    }
    else
    return 0;
}


#endif